...one that I'd really like to visit in the south of England is Crossness.

Just look at the pride the Victorians took in building magnificent cathedral of engineering - it's like some elaborate masonic hall.

Wow, yes Peter -

I just re-watched the video but this time at a more relaxed pace. Absolutely stunning. Seems to me that Crossness and Kempton Park are two awe-inspiring examples, each in its own way, both from very different stages of the steam era.

Yes indeed Chris. When I was there a few years ago, some of the other engines in their collection were running but this one wasn't. It was still magnificent though - the atmosphere in the engine house was like that of a temple, with its lofty fluted columns and strange sense of stillness. I felt this, and others have said similar.

Next time I go there, though, I'll make sure it's on a day when it's running.

Meanwhile, back to an engine which is slightly smaller and a tiny bit less sophisticated than the above.

Slow progress.

The photo below shows the new cylinder blank, which is now the correct length of 30mm. Also, my metric reamers arrived and I have drilled and reamed the flywheel to 6mm, and have faced the rim and hub of one side of it..

So far so good. However, I have struggled with the main axle. The plans ask for a length of 6mm diameter silver steel. I didn't have any, so decided to turn down some thicker stock. It's not the money, as silver steel is cheap as chips in small quantities - I just thought 'use what you have'. The attempt shown in a previous post turned out to be tapered, so I abandoned it and adjusted my lathe tailstock. Since then I have been wasting metal, creeping up on the required diameter... and then past it to create a too-narrow axle and a slightly rattly fit for the flywheel. The last effort was the best, but I still wasn't happy with it and have rejected it.

This reveals my inexperience. It has been a frustrating couple of evenings. I then found some steel which is about 5.85mm diameter, which I had overlooked. The flywheel slides along it nicely, but still rocks a bit from side to side if encouraged to do so. The bearing worries me too, as it will be drilled and reamed for the same 6mm shaft.Part of the problem is that I don't know what to expect and what would be considered acceptable, but I assume that I should be looking for a nice sliding fit with no lateral play. Am I correct?

Meanwhile, I'm just going to temporarily admit defeat and order some 6mm silver steel, which hopefully will do the trick and at the very least will give me a baseline idea of how well these things can be expected to fit together 'off the shelf'. For all I know at this point it still might not be perfect... That said, it does occur to me that keeping a small stock of round bars of various diameters might be smarter than turning down to diameter every time one wants to make a straight shaft.

Overall, a humbling experience showing me that I have a lot to learn about accurate turning. I'll need to up my game when it comes to the piston on this engine and all kinds of parts on subsequent builds . Any advice welcome...

So, the picture shows the story so far, but tbh I had hoped to be further on at this point. But having spent a day and a half sanding and varnishing floors this week I can probably feel justified in some extra shop time over the weekend...

Welcome to the fun. Fits and clearances are something I still struggle with to a certain extent. In general terms being a little undersized is ok. Putting a 6mm shaft into a 6mm hole is a press fit. That is not what you want on your bearings. I usually try to be 2-3 thousands of an in ( about .05 to .07 mm if my math is correct ) smaller for a bearing fit. I use the same fit on my flywheels. The reality is that when I started I was lucky if I could hold +/- 8-10 thousandths (.2 - .25 mm) on my first few engines and they worked just fine. Your fits will improve with time and experience.

Welcome to the fun. Fits and clearances are something I still struggle with to a certain extent. In general terms being a little undersized is ok. Putting a 6mm shaft into a 6mm hole is a press fit. That is not what you want on your bearings. I usually try to be 2-3 thousands of an in ( about .05 to .07 mm if my math is correct ) smaller for a bearing fit. I use the same fit on my flywheels. The reality is that when I started I was lucky if I could hold +/- 8-10 thousandths (.2 - .25 mm) on my first few engines and they worked just fine. Your fits will improve with time and experience.

Tony

@ Tony - that is very reassuring. Much appreciated. TBH I was thinking that maybe it's just me. I don't mind having a learning curve to negotiate, which is different from feeling a failure and giving up (which I have no intention of doing). Knowing that you and others have been there too gives me vital encouragement. What I'll do now is shift to other parts until the 6mm steel arrives, then look at my options for the shaft when it does. Will report back on that later.

@ Dave and Bill - thanks for the encouragement. It helps, and really is appreciated